1. Field of the Invention
The present invention relates to an image recording apparatus and an image reproducing apparatus for recording and reproducing a three-dimensional image and, more particularly, to those that permit an observer to observe a three-dimensional image, recorded in an image recording means, in a natural and good state tirelessly.
2. Related Background Art
A variety of methods have been attempted heretofore for recording image information of a stereoscopic object (three-dimensional object) in the image recording means and stereoscopically reproducing the image information recorded in the image recording means.
Among these methods, the IP (integral photo) method is often used as a method for recording and reproducing the three-dimensional image without use of special glasses or the like. FIG. 9A and FIG. 9B are explanatory diagrams to show a three-dimensional image recording apparatus and a three-dimensional image reproducing apparatus according to this method.
In FIG. 9A reference numeral 101 designates a microlens array called a fly's eye lens which is a two dimensional array of microscopic lenses 101a, as shown in FIG. 10, like a compound eye of an insect.
A photographic plate 102 is placed behind the microlens array 101. Microscopic inverted images 104 of subject 103 are formed on the photographic plate 102 by the respective lenses 101a to expose the dry plate to be recorded therein. A positive (positive image) is made in the same size from the photographic plate 102 in which the image information was recorded. The microlens array 101 as illustrated in FIG. 9B is placed correctly at the original position on the front surface of the substrate 102a thus made and the substrate 102a is illuminated from its back.
Beams from the respective images in the positive recorded in the substrate 102a travel backward in the same paths as during the photographing operation to reproduce a three-dimensional real image 105 at the original position of the subject. An observer 106 observes this real image 105 thus reproduced.
The three-dimensional image recording and reproducing apparatus illustrated in FIGS. 9A and 9B had the following problems. First, they were able to record and reproduce only stereoscopic image information of actually existing subjects. Therefore, a virtual three-dimensional object formed arbitrarily had to be recorded and reproduced by other methods.
Second, the depth of focus of the microlens array 101 is not so deep, so that a blur appears in the recorded images. In the IP method, because the subject 103 has depths during recording of the three-dimensional image, distances from the photographic plate 102 differ depending upon portions of the subject.
Since the microlenses of the microlens array have a constant focal length, each of images off the focal depth among the inverted images formed on the photographic plate includes a defocus. Therefore, deterioration of quality of image occurs due to the defocus in the three-dimensional image recorded and reproduced in this state.
Third, the three-dimensional image reproduced becomes a pseudo-stereoscopic image in certain cases. FIG. 11 and FIG. 12 are explanatory diagrams to explain such a case. FIG. 11 shows a state during the recording operation of a three-dimensional image. In the same figure image information of side B of the subject 103 is recorded on the photographic plate 102.
FIG. 12 shows a state in which this IP recorded in the photographic plate 102 is reproduced. As illustrated in FIG. 12, the observer observes the image from side A of the three-dimensional image 103, but the information of the image recorded in the photographic plate 102 includes only the image information of side B.
Therefore, the three-dimensional image 103 is seen as if the back side of the object is seen through and in addition, projections and depressions of the image information are observed in an inverse state.